import es6 from '../assets/plugins/es6-promise.js'
import Tool from './Tool.js'

class WechatService{
  constructor(){
    this._init()
  }
  //初始化方法
  _init(){
    const that = this
    that.tool = new Tool()

    //缓存非异步方法
    that.noPromiseMethods=[
      'stopRecord',
      'pauseVoice',
      'stopVoice',
      'pauseBackgroundAudio',
      'stopBackgroundAudio',
      'showNavigationBarLoading',
      'hideNavigationBarLoading',
      'createAnimation',
      'createContext',
      'hideKeyboard',
      'stopPullDownRefresh',
    ]

    // 缓存wx接口方法名
    that.instanceSource = {
      method: Object.keys(wx)
    }

    // 遍历wx方法对象，判断是否为异步方法，是则构造promise
    for (let key in that.instanceSource) {
      that.instanceSource[key].forEach(function (method) {
        that[method] = function () {
          // 判断是否为非异步方法或以 wx.on 开头，或以 Sync 结尾的方法
          if (that.noPromiseMethods.indexOf(method) !== -1 || method.substr(0, 2) === 'on' || /\w+Sync$/.test(method)) {
            return wx[method](...Array.from(arguments))
          }
          return that.__getPromise(es6.Promise, that.__getResolver(that.__defaultRequest, [method, ...Array.from(arguments)], that))
        }
      })
    }

    /**
     * 保留当前页面，跳转到应用内的某个页面
     * @param {String} url  路径
     * @param {Object} params 参数
     */
    that.navigateTo = (url, params) => {
      const $$url = that.tool.buildUrl(url, params)
      return new es6.Promise((resolve, reject) => {
        wx.navigateTo({
          url: $$url,
          success: res => resolve(res),
          fail: res => reject(res),
        })
      })
    }

    /**
     * 关闭当前页面，跳转到应用内的某个页面
     * @param {String} url  路径
     * @param {Object} params 参数
     */
    that.redirectTo = (url, params) => {
      const $$url = that.tool.buildUrl(url, params)
      return new es6.Promise((resolve, reject) => {
        wx.redirectTo({
          url: $$url,
          success: res => resolve(res),
          fail: res => reject(res),
        })
      })
    }

  }

  /**
   * __getPromise
   */
  __getPromise(Promise, resolver) {
    if (Promise) return new Promise(resolver)
    throw new Error('Promise library is not supported')
  }

  /**
   * __getResolver
   */
  __getResolver(method, args, context) {
    return function (resolve, reject) {
      method.apply(context, args)(resolve, reject)
    }
  }

  /**
   * 以wx下API作为底层方法
   * @param {String} method 方法名
   * @param {Object} obj    接收参数
   */
  __defaultRequest(method = '', obj = {}) {
    return function (resolve, reject) {
      obj.success = (res) => resolve(res)
      obj.fail = (res) => reject(res)
      wx[method](obj)
    }
  }
}
export default WechatService